Animal Physiology Research Articles

Bridging the divide in organismal physiology: a case for the integration of behaviour as a physiological process.

The role of behaviour in animal physiology is much debated, with researchers divided between the traditional view that separates physiology and behaviour, and a progressive perspective that sees behaviour as a physiological effector. We advocate for the latter, and in this Commentary, we argue that behaviour is inherently a physiological process. To do so, we outline the physiological basis for behaviour and draw parallels with recognised physiological processes. We also emphasise the importance of precise language that is shared across biological disciplines, as clear communication is foundational in integrating behaviour into physiology. Our goal with this Commentary is to set the stage for a debate and persuade readers of the merits of including behaviour within the domain of animal physiology. We argue that recognising behaviour as a physiological process is crucial for advancing a unified understanding of physiology, especially in the context of anthropogenic impacts.

Artificial Light at Night Advances the Onset of Vocal Activity in Both Male and Female Great Tits During the Breeding Season, While Noise Pollution Has Less Impact and Only in Females

Artificial light at night (ALAN) and noise pollution are two important stressors associated with urbanisation that can have a profound impact on animal behaviour and physiology, potentially disrupting biological rhythms. Although the influence of ALAN and noise pollution on daily activity patterns of songbirds has been clearly demonstrated, studies often focus on males, and the few that examined females have not included the potential influence of males on female activity patterns. Using free-living pairs of great tits (Parus major) as a model, we examined for the first time the effects of ALAN and noise pollution and their interaction on the onset of (vocal) activity in both members of a pair. We focused on the egg-laying phase, when both sexes are most vocally active. The onset of male dawn song, female emergence time from the nest box and the onset of female calling in the nest box were measured and used as a proxy for the chronotype. The repeatabilities for all chronotype proxies were high, with higher repeatabilities for males. Consistent with previous studies, ALAN advanced the onset of male dawn song, while it did not elicit a strong response in female emergence time. Additionally, our results suggest an indirect effect of ALAN on the onset of female vocal activity via acoustic interaction with the male. Noise pollution advanced the emergence time in females, while an interaction between ALAN and noise pollution was found for the onset of female calling. In agreement with previous studies, several covariables were shown to have an influence on the activity onset. Taking several proxies for chronotype into account, this study has provided robust evidence of effects of ALAN on male and female cavity-nesting songbirds during the egg-laying period.

Revolutionizing new drug discovery: Harnessing AI and machine learning to overcome traditional challenges and accelerate targeted therapies

Designing highly targeted, selective drugs with desirable absorption, distribution, metabolism, excretion, and pharmacokinetic (PK) profiles; single-digit nanomolar efficacy; and a wider therapeutic index are challenging. In the traditional drug discovery process, researchers screen thousands of chemical compounds during pre-clinical development, progressing through hit identification, lead optimization, and candidate selection to shortlist – potential clinical candidates with favorable PK profiles, high tolerability, and manageable toxicity. The selected candidate must demonstrate sufficient efficacy in treating the target disease in humans. Despite these efforts, the success rate of the pre-clinical candidate to sail through Phase I, Phase II, and Phase III in clinical trials remains exceedingly low. Supported by powerful data-driven tools, artificial intelligence (AI) has transformed this traditional drug discovery process by enabling the analysis of large quantities of omics, phenotypic, and expression data to identify the biological mechanisms of pathological conditions and in turn identify druggable proteins or genes. The generative AI-powered toolbox creates novel compounds from scratch, assists scientists in optimizing druggability attributes, and bridges the differences between animal and human physiology and anatomy to predict potential toxicity in humans with high accuracy. This review discusses the bottlenecks in the traditional drug discovery approach, the impact of AI and machine learning (ML) in drug discovery, and potential challenges associated with AI/ML adoption.

Curcumin enhances developmental competence and ameliorates heat stress in in vitro buffalo (Bubalus bubalis) embryos

Background and Aim: Buffalo is the principal dairy animal and plays a major role in the economic growth of the dairy industry, contributing nearly 50% of the country’s milk production. The Buffalo core body temperature is typically 38.5°C, but it can rise to 41.5°C in the summer, causing heat stress, which leads to the generation of reactive oxygen species or oxidative stress and affects the reproductive physiology of animals. Curcumin acts as an antioxidant, improves cellular development, and combats the effect of heat stress on in vitro-produced embryos. This study aimed to examine the impact of curcumin on developmental competence and the expression of important genes under normal and heat-stressed conditions during in vitro embryo production in buffalo. Materials and Methods: Group-1: All embryo production steps (i.e., in vitro maturation [IVM], in vitro fertilization [IVF], and in vitro culture [IVC]) were conducted at 38.5°C. The presumed zygotes were cultured in media supplemented with different concentrations of curcumin, that is, 0 μM, 5 μM, and 10 μM of curcumin. Group-2: All embryo production steps (i.e., IVM, IVF, and IVC) were carried out at 38.5°C. The presumed zygotes were cultured in media supplemented with different concentrations of curcumin, that is, 0 μM, 5 μM, and 10 μM of curcumin, but the early cleaved embryos were exposed to heat stress (39.5°C) for 2 h after 48 h of IVF and then cultured at 38.5°C for embryo production. Results: Blastocyst production was 16.63 ± 1.49%, 21.46 ± 0.67%, and 6.50 ± 1.17% at control, 5 μM and 10 μM of curcumin at 38.5°C, respectively, whereas at 39.5°C, it was 8.59 ± 1.20%, 15.21 ± 1.31%, and 3.03 ± 1.20% at control, 5 μM and 10 μM curcumin, respectively. The blastocyst rate was found to be significantly higher (p < 0.05) at 5 μM curcumin compared with the control or 10 μM at 38.5°C and 39.5°C. The antioxidant, antiapoptotic, and pluripotency-related genes exhibited higher (p < 0.05) expression in the presence of 5 μM curcumin compared to 10 μM or control at both temperatures. Conclusion: Curcumin supplementation in embryo culture media effectively enhances embryo production in vitro and mitigates the adverse effects of heat stress. Keywords: antioxidant, buffalo, curcumin, embryo, heat stress.

ECR Spotlight – Matthew Gilbert

ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Matthew Gilbert is an author on ‘ Measuring maximum heart rate to study cardiac thermal performance and heat tolerance in fishes’, published in JEB. Matthew is an Assistant Professor of Animal Physiology at the Institute of Arctic Biology, University of Alaska Fairbanks, USA, investigating environmental drivers of cardiorespiratory and energetic plasticity, thermal physiology and exercise physiology.

Current advances in physiological science. In commemoration of centennial anniversary of the Department of Human and Animal Physiology of Moscow State University

Hereby we briefly review the articles that comprise the special issue of “Lomonosov Biology Journal” (“Vestnik Moskovskogo universiteta. Seria 16. Biologia”), which commemorates the centennial anniversary of the Department of Human and Animal Physiology of Lomonosov Moscow State University, founded by prominent Russian physiologist Alexander F. Samoilov. The main stages of the Department’s history are briefly described. The published studies of the leading Russian researchers, including the scientific research group from Department of Human and Animal Physiology, are discussed within the scope of main current challenges of physiological science.

The Reindeer Circadian Clock Is Rhythmic and Temperature-compensated But Shows Evidence of Weak Coupling Between the Secondary and Core Molecular Clock Loops.

Circadian rhythms synchronize the internal physiology of animals allowing them to anticipate daily changes in their environment. Arctic habitats may diminish the selective advantages of circadian rhythmicity by relaxing daily rhythmic environmental constraints, presenting a valuable opportunity to study the evolution of circadian rhythms. In reindeer, circadian control of locomotor activity and melatonin release is weak or absent, and the molecular clockwork is reportedly non-functional. Here we present new evidence that the circadian clock in cultured reindeer fibroblasts is rhythmic and temperature-compensated. Compared with mouse fibroblasts, however, reindeer fibroblasts have a short free-running period, and temperature cycles have an atypical impact on clock gene regulation. In reindeer cells, Per2 and Bmal1 reporters show rapid responses to temperature cycles, with a disintegration of their normal antiphasic relationship. The antiphasic Per2-Bmal1 relationship re-emerges immediately after release from temperature cycles, but without complete temperature entrainment and with a marked decline in circadian amplitude. Experiments using Bmal1 promoter reporters with mutated RORE sites showed that a reindeer-like response to temperature cycles can be mimicked in mouse or human cell lines by decoupling Bmal1 reporter activity from ROR/REV-ERB-dependent transcriptional regulation. We suggest that weak coupling between core and secondary circadian feedback loops accounts for the observed behavior of reindeer fibroblasts in vitro. Our findings highlight diversity in how the thermal environment affects the temporal organization of mammals living under different thermoenergetic constraints.

Small ORFs, Big Insights: Drosophila as a Model to Unraveling Microprotein Functions.

Recently developed experimental and computational approaches to identify putative coding small ORFs (smORFs) in genomes have revealed thousands of smORFs localized within coding and non-coding RNAs. They can be translated into smORF peptides or microproteins, which are defined as less than 100 amino acids in length. The identification of such a large number of potential biological regulators represents a major challenge, notably for elucidating the in vivo functions of these microproteins. Since the emergence of this field, Drosophila has proved to be a valuable model for studying the biological functions of microproteins in vivo. In this review, we outline how the smORF field emerged and the nomenclature used in this domain. We summarize the technical challenges associated with identifying putative coding smORFs in the genome and the relevant translated microproteins. Finally, recent findings on one of the best studied smORF peptides, Pri, and other microproteins studied so far in Drosophila are described. These studies highlight the diverse roles that microproteins can fulfil in the regulation of various molecular targets involved in distinct cellular processes during animal development and physiology. Given the recent emergence of the microprotein field and the associated discoveries, the microproteome represents an exquisite source of potentially bioactive molecules, whose in vivo biological functions can be explored in the Drosophila model.

The role of NMDA receptors in fish stress response: Assessments based on physiology of the caudal neurosecretory system and defensive behavior.

Stress strongly influences the physiology and behavior of animals, and leads into a pathological condition and disease. NMDA receptors (NMDARs) play a crucial role in the modulation of neural activity. To understand the role of NMDARs in fish stress response, we used NMDARs agonist aspartate to test the functional role of its input on the Dahlgren cell population in the caudal neurosecretory system (CNSS) of the olive flounder. In addition, the effect of the NMDARs antagonist D-AP5 on the expression of genes of the main secretory products of the CNSS after stress was investigated by using qPCR technology and the effect of the NMDARs antagonist D-AP5 on post-stress behavior was explored by behavioral methods. Ex vivo electrophysiological experiments showed that the NMDARs agonist aspartate enhanced the firing frequency of Dahlgren cells. Additionally, aspartate treatment increased the incidence of cells exhibiting bursting firing pattern, this result is corroborated by the observed upregulation in the expression of ion channels and major hormone genes in the CNSS. Furthermore, the excitatory influence of aspartate was effectively counteracted by NMDARs antagonist D-AP5. Interestingly, NMDARs antagonist D-AP5 treatment also significantly decreased the plasma cortisol levels and the expression of CRH, UI, and UII in CNSS after acute stress. Treatment with D-AP5 effectively attenuated the stress response, as evidenced by alterations in respiratory metabolism, sand-burying behavior, swimming distance, simulated capture, and escape response. In conclusion, modulation of Dahlgren cell excitability in the CNSS by NMDARs contributes to the regulation of the stress response, NMDARs antagonist D-AP5 can effectively suppress stress response in flounder by regulating the stress hormone expression and secretion. CLINICAL TRIAL REGISTRATION: Project code SHOU-DW-2022-032.

Microfluidics-A novel technique for high-quality sperm selection for greater ART outcomes.

Microfluidics represent a quality sperm selection technique. Human couples fail to conceive and this is so in a significant population of animals worldwide. Defects in male counterpart lead to failure of conception so are outcomes of assisted reproduction affected by quality of sperm. Microfluidics, deals with minute volumes (μL) of liquids run in small-scale microchannel networks in the form of laminar flow streamlines. Microfluidic sperm selection designs have been developed in chip formats, mimicking invivo situations. Here sperms are selected and analyzed based on motility and sperm behavioral properties. Compared to conventional sperm selection methods, this selection method enables to produce high-quality motile sperm cells possessing non-damaged or least damaged DNA, achieve greater success of insemination in bovines, and achieve enhanced pregnancy rates and live births in assisted reproduction-in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). Besides, the concentration of sperm available to oocyte can be controlled by regulating the flow rate in microfluidic chips. The challenges in this technology are commercialization of chips, development of fully functional species-specific microfluidic tools, limited number of studies available in literature, and need of thorough understanding in reproductive physiology of domestic animals. In conclusion, incorporation of microfluidic system in assisted reproduction for sperm selection may promise a great success in IVF and ICSI outcomes. Future prospectives are to make this technology more superior and need to modify chip designs which is cost effective and species specific and ready for commercialization. Comprehensive studies in animal species are needed to be carried out for wider application of microfluidic sperm selection in invitro procedures.

Differences in body condition and hepatic cellular metabolism among distinct populations of cestode-infected pumpkinseed sunfish (Lepomis gibbosus)

Host populations can vary in the prevalence and intensity of their parasites, which may influence the impacts of infection on host physiology and health. Parasite-induced effects on hosts may be due to underlying changes in cellular energy metabolism, predominantly driven by the mitochondria. However, limited research has been conducted on understanding variation in host–parasite interactions across populations. We sampled three wild populations of pumpkinseed sunfish ( Lepomis gibbosus (Linnaeus, 1758)), two of which are infected by cestodes, to study correlations among infection intensity, host body condition, and key metabolic enzyme activities in liver tissue. In both infected populations, cestode infection was associated with reduced hepatic lipid metabolism and increased hepatic lactic fermentation. Interestingly, Lake Cromwell fish showed a decrease in body condition, electron transport system activity, and antioxidant activity with cestode intensity, whereas the contrary was observed for Lake Long fish. This suggests that Lake Long fish could be boosting their immune system and food intake to better tolerate infection, unlike Cromwell fish. This study not only highlights how different populations can vary in their response to parasite infections but also the importance of accounting for infection when studying animal physiology.

The impact of sugar diet on humidity preference, survival, and host landing in mosquitoes.

Mosquito-borne diseases have caused more than one million deaths each year. There is an urgent need to develop an effective way to reduce mosquito-host interaction to mitigate disease transmission. Sugar diets have long been linked to abnormal physiology in animals, making them potential candidates for mosquito control. Here, we show the impact of sugar diets on humidity preference and survival in Aedes aegypti and Culex pipiens . With two-choice assays between 100% and 75% relative humidity (RH), we demonstrate that the effect of sugar diets on humidity preference is species-specific where Ae. aegypti showed significant differences and the reduced effects were noted in Cx. pipiens . Among the sugar diets, arabinose significantly reduced the survival rate of mosquitoes even at low concentrations. Moreover, we found that host landing was not impacted by feeding on different sugar types. Our study suggests that specific sugar treatments could be applied to mosquito control by dampening their humidity preference and reducing their lifespan, thus reducing mosquito-borne disease transmission.

Controlled elevation of intraocular pressure in anesthetized mice

Our purpose was to develop a protocol for prolonged anesthesia in mice and evaluate optic nerve axon injury in response to 4 h of controlled elevation of intraocular pressure (CEI). During CEI, C57BL/6 male mice (3–5 months old) were anesthetized with 1.5% isoflurane with 100% oxygen for 4 h and placed on a warm platform, with expired gas and anesthetic actively evacuated. Lactated ringers (0.5 ml) with 5% dextrose was administered subcutaneously at the start and end of CEI. Physiological parameters (oxygen saturation = O2, heart rate = HR, systolic blood pressure = SBP, and temperature) were monitored throughout the 4-h CEI. One eye was cannulated with polyurethane tubing connected to a balanced salt solution reservoir and IOP elevated to 20 (N = 18), 30 (N = 13), 50 (N = 14), and 60 mmHg (N = 16). An additional group of 22 female mice was exposed to CEI of 60 mmHg. Fourteen days after CEI, optic nerves were assessed for axonal injury by masked observers that assigned a grade on a scale from 1 (normal) to 5 (>50% of axons degenerating). CEI optic nerve injury was compared to injury assessed in contralateral optic nerves (N = 84) and naïve optic nerves (N = 18) using a one-way ANOVA followed by Kruskal-Wallis test for multiple comparisons. The relationship between optic nerve injury, physiological parameters, and IOP were assessed by linear regression analyses. Physiologic parameters remained stable throughout CEI (O2 = 95 ± 9%; HR = 450 ± 39; SBP = 102 ± 15 mmHg, and temperature = 38 ± 0.7 °C) and were not statistically different between groups (all comparisons had P > 0.5). Mean optic nerve injury grades (±SD) for naïve optic nerves (1.01 ± 0.02) were not significantly different from fellow/contralateral optic nerves (1.03 ± 0.07, P > 0.99), or from CEI of 20 mmHg (1.04 ± 0.08, P > 0.99) or 30 mmHg (1.05 ± 0.06, P = 0.6). However, animals exposed to CEI of 50 mmHg (2.09 ± 1.43, P = 0.0005) and 60 mmHg (male: 2.86 ± 1.30, P < 0.0001, female: 1.63 ± 1.00, P = 0.0006) developed significant optic nerve injury relative to their fellow/contralateral optic nerves. Axonal injury grades following a CEI of 60 mmHg were not significantly different between male and female mice (P = 0.19). Optic nerve injury positively correlated (P < 0.0001) with IOP and not with physiological parameters, indicating that the optic nerve injury is IOP-related. In conclusion, prolonged anesthesia in mice requires careful attention to animal physiology. With this, a 4-h exposure to elevated IOP can produce significant optic nerve injury with IOPs equal to or greater than 50 mmHg. We provide detailed descriptions of methods and materials for producing prolonged elevations of IOP in mice while maintaining and monitoring their physiology, as well as a unique, cost-effective transducer system for monitoring pressure delivery.

Mammals show faster recovery from capture and tagging in human-disturbed landscapes

Wildlife tagging provides critical insights into animal movement ecology, physiology, and behavior amid global ecosystem changes. However, the stress induced by capture, handling, and tagging can impact post-release locomotion and activity and, consequently, the interpretation of study results. Here, we analyze post-tagging effects on 1585 individuals of 42 terrestrial mammal species using collar-collected GPS and accelerometer data. Species-specific displacements and overall dynamic body acceleration, as a proxy for activity, were assessed over 20 days post-release to quantify disturbance intensity, recovery duration, and speed. Differences were evaluated, considering species-specific traits and the human footprint of the study region. Over 70% of the analyzed species exhibited significant behavioral changes following collaring events. Herbivores traveled farther with variable activity reactions, while omnivores and carnivores were initially less active and mobile. Recovery duration proved brief, with alterations diminishing within 4–7 tracking days for most species. Herbivores, particularly males, showed quicker displacement recovery (4 days) but slower activity recovery (7 days). Individuals in high human footprint areas displayed faster recovery, indicating adaptation to human disturbance. Our findings emphasize the necessity of extending tracking periods beyond 1 week and particular caution in remote study areas or herbivore-focused research, specifically in smaller mammals.

340 Training cognitive skills to improve integration and application of knowledge in animal physiology

Abstract Case-based learning immerses students in real-world scenarios, prompting observation, action, and reflection to enhance cognitive skills. The open-ended nature of such learning can challenge students to reach greater levels of critical thinking; however, we have noticed that without guidance, students often do not know how to approach these types of questions. Therefore, the objective of this study was to investigate how two low-input interventions strategies may help train cognitive skills and improve student performance. Three semesters of an undergraduate physiology course employed a case-based assessment strategy, which included three-unit case studies and one cumulative final case study. Semester 1 (S1; n = 48) represented no intervention, Semester 2 (S2; n = 59) included two dedicated class periods of instructor led guidance on approaching case studies, and Semester 3 (S3; n = 95) utilized an online peer evaluation platform, where students evaluated and provided feedback to each other. For S2 and S3 the interventions first took place between case study 1and case study 2. In all semesters, students also received individualized feedback from the instructor or teaching assistants after each case study. In S2 and S3 pre-semester and post-semester surveys were administered to understand changes in perceptions of their own cognitive skills. In S2 and S3, case study grades decreased and increased (P &amp;lt; 0.05), respectively, between the first and second case study. The average grade on case studies after intervention was greatest (P &amp;lt; 0.05) in S3 where peer intervention was employed, compared with S1 or S2, which did not differ. When comparing changes in perceptions between the beginning and end of the semester, student confidence in their cognitive skills, determined by agreeance with Likert scale statements, tended to increase more (P &amp;lt; 0.10) in S3 compared with S2 (7.9% vs. 3.4%, respectively). The most notable change was agreeance with the statement “I can take multiple ideas from different concepts and combine them to create new understanding” which increased 7.0% and 16.5% in S2 and S3, respectively. Interestingly, free response questions indicated that students did not enjoy peer evaluation and felt that it was not beneficial to their learning. However, these data indicate that students benefited most from peer led intervention, when evaluated by student performance and perceptions of their cognitive skills. Peer evaluation provides a unique opportunity for students to actively engage in the learning process and to practice cognitive skills. This process holds dual benefit as reviewing peers requires students to reflect, analyze, and evaluate, which are cognitive skills also needed to solve the case studies.

13 Awardee Talk: Goals, methods, and philosophy of graduate mentoring in reproductive physiology

Abstract Successful graduate and postdoctoral training programs in reproductive physiology are reciprocal relationships that, by default, benefit both trainee and mentor. Ideally, goals are for the mentor to facilitate and guide the long-term educational and professional aspirations of the trainee, while simultaneously creating an important member of the research team capable of meaningful contributions to the scientific enterprise. When this partnership fails to develop and flourish in a transparent and collaborative manner, the resulting disequilibrium leads to negative and costly impacts. Over the last 50 yr, I have observed the importance of several principles that, in my opinion, have a major influence on this process. The first of these begins at student recruitment and during the early part of a program after acceptance. Here, a clear understanding of any academic deficiencies and a commitment to rectify these deficiencies is essential. Academic programs of promising M.S. level candidates are sometimes heavily encumbered by this task. In contrast, Ph.D. programs are usually the final opportunity to take advantage of cutting-edge courses related to or supportive of reproductive biology and should be encouraged. Second, early development of a functional advisory committee is important and contributes broad experience and wisdom to the unique strengths and weaknesses of every student. Third, the trainee must learn early on the value of a mature attitude, a strong work ethic, and personal accountability. As an animal scientist, I want every student to be well-versed with hands on training/experience in basic animal physiology, nutrition, reproduction, experimental (surgical) techniques, and husbandry. Concurrently, they must learn to ensure that the well-being and ethical treatment of research animals always comes first. The foregoing is accomplished through personal example and never asking a student to do something you cannot or will not do yourself. Fourth, pursuing modern, cutting-edge techniques in the laboratory, regardless of long-term personal goals, should be an educational and experiential requirement. Fifth, development of meaningful and sound research projects requires hours of reading, thought and discussion. Students, particularly at the M.S. level, are often completely lost relative to the path forward. Allowing trainees to adopt pre-planned experiments within existing projects in the lab, with the mandate of developing new hypotheses and expanding beyond initial objectives, is a common theme. Pragmatically, this is also essential for maintaining laboratory focus and to service federal, state, and industry-funded projects effectively. Nonetheless, learning to develop and test new and sound hypotheses using appropriate experimental designs remains essential. Finally, no other factor has a greater impact on trainee success than the ability to communicate effectively using the English language. Unfortunately, this topic and problems associated with it usually form the caboose of most graduate training programs when it should have formed the engine.

276 Use of triaxial accelerometers and a machine learning algorithm for behavioral identification to assess the effectiveness of a joint supplement in old domestic cats (Felis catus)

Abstract Degenerative joint disease (DJD) has a 90% prevalence in older cats and adversely affects quality of life1. Long-term administration of non-steroidal anti-inflammatory drugs is usually required but can have adverse effects2. Nutraceuticals have been shown to relieve joint pain in cats without such side effects; however, due to differences in dose rates and formulations there is no consensus as to their efficacy. Most studies have utilized subjective insensitive measures such as veterinary or owner-assessed changes in activity. Accelerometers can provide objective data on cat activity and can identify specific behaviors3.Triaxial accelerometers (ActiGraph, Pensacola, FL) were fitted to the collars of 16 cats (aged 11 to 16 yr; Massey University, Palmerston North, NZ) for 20 wk to assess their activity and behavior. The cats were fed the same diet (Chef: Kraft Heinz Wattie’s Ltd., Hastings, NZ) for 4 wk to collect baseline acceleration data, before being divided into two groups balanced for physical activity. After 4 wk, a blood sample were taken from all of the cats to establish their baseline levels of a range of inflammatory markers (e.g., IL-6, TNFα, INF- γ, SDF-1). The test group (n = 8) then received a joint supplement added to the baseline diet while the control group (n = 8) were fed the diet unsupplemented for 16 wk. The commercial joint supplement contained glucosamine, chondroitin sulphate, and green-lipped mussel (Tandem, Wellington, NZ), at daily doses shown previously to be effective in cats4,5,6. The aim of the work was to assess the efficacy of the joint supplement in maintaining or promoting activity and specific behaviors in the cats. At the end of the period of supplementation a second blood sample was taken and assessed for the same range of inflammatory markers. Overall physical activity was not different between groups at baseline but was greater over the study in the test group compared with the control (P &amp;lt; 0.03). Grooming, as identified by the algorithm, showed a tendency (P = 0.051) to be greater in the test group than the control. These results suggest that the supplement had a positive effect on both overall activity and more specifically on grooming behavior in old cats. However, no differences in the range of inflammatory markers were seen before or after supplementation. While the behavioral measures could indicate the supplement reduced the effects of DJD, further research is required to confirm this.1Cunningham et al (2022) Journal of Feline Medicine and Surgery 24, 962-974. 2Lemetayer and Taylor (2014) Journal of Feline Medicine and Surgery 16, 547-562; 3Smit et al., (2023) Sensors 23, 7165; 4Corbee (2022) Veterinary Medicine and Science 8, 1025–1035; 5Corbee et al. (2013) Journal of Animal Physiology and Animal Nutrition 97, 846–853; 6Lascelles et al. (2010) Journal of Veterinary Internal Medicine, 24, 487–495.

Paracellular barriers: Advances in assessing their contribution to renal epithelial function

Regulation of salt and water balance occupies a dominant role in the physiology of many animals and often relies on the function of the renal system. In the mammalian kidney, epithelial ion and water transport requires high degree of coordination between the transcellular and paracellular pathways, the latter being defined by the intercellular tight junctions (TJs). TJs seal the paracellular pathway in a highly specialized manner, either by forming a barrier against the passage of solutes and/or water or by allowing the passage of ions and/or water through them. This functional TJ plasticity is now known to be provided by the members of the claudin family of tetraspan proteins. Unlike mammalian nephron, the renal structures of insects, the Malpighian tubules, lack TJs and instead have smooth septate junctions (sSJs) as paracellular barrier forming junctions. Many questions regarding the molecular and functional properties of sSJs remain open but research on model species have begun to inform our understanding. The goal of this commentary is to highlight key concepts and most recent findings that have emerged from the molecular and functional dissection of paracellular barriers in the mammalian and insect renal epithelia.

Differential growth enhancement followed by notable microbiota modulation in growing-finishing pigs by Bacillus subtilis strains ps4060, ps4100, and a 50:50 strain mixture.

A 50:50 blend of two Bacillus subtilis strains positively impacted the productivity of finishing pigs. Given this observed effect, we hypothesized that each strain has distinct effects on weight gain and their influence on gut microbiota. In a 16-week test, 160 pigs were divided into four groups: basal diet, B. subtilis ps4100, B. subtilis ps4060, and 50:50 mixture supplemented. Subsequently, we compared body weight and fecal microbiota. Among the supplements, ps4100, ps4060, and the 50:50 mix yielded respective average daily weight gains (ADG) of 3.6%, 4.6%, and 3.9% by the 6th week. The weight difference was maintained through the 16th week. At the 11th week, the difference in α-diversity among the fecal microbiota was marginal, and 17 of 229 genera showed differential abundance between the control and either of the treatment groups. A total of 12 of the 17 genera, including Lactobacillus, showed differential abundance between the ps4100 and ps4060-fed groups, and only Eubacterium consistently decreased in abundance in both the ps4100 and ps4060 groups. In comparison, microbial diversity was significantly different at the 16th week (p < 0.05), with 96 out of 229 genera exhibiting differential abundance. A total of 42 of the 96 genera exhibited similar patterns in both the ps4100 and ps4060 groups compared to the control group. Additionally, 236 of 687 microbial enzymes with differential abundance deduced from 16S rRNA reads showed similar differential abundance in both groups compared to the control group. We concluded that the overall microbial balance, rather than the dominance or significant decrease of a few specific genera, likely caused the enhanced ADG until the 11th week. Substantial changes in microbiota manifested at the 16th week did not cause dramatically increased ADG but were a consequence of weight gain and could positively affect animal physiology and health afterward.

Nutritional Strategies to Alleviate Stress and Improve Welfare in Dairy Ruminants.

Dairy ruminants provide a major part of the livestock and agriculture sectors. Due to the increase in world population and the subsequent increase in dairy product demands, the dairy sector has been intensified. Dairy farming intensification and the subsequent increase in animal nutritional demands and the increase in the average global temperature as well have subjected animals to various stress conditions that impact their health and welfare. Various management practices and nutritional strategies have been proposed and studied to alleviate these impacts, especially under heat stress, as well as during critical periods, like the transition period. Some of the nutritional interventions to cope with stress factors and ensure optimal health and production are the inclusion of functional fatty acids and amino acids and feed additives (minerals, prebiotics, probiotics, essential oils and herbs, phytobiotics, enzymes, etc.) that have been proven to regulate animals' metabolism and improve their antioxidant status and immune function. Thus, these nutritional strategies could be the key to ensuring optimum growth, milk production, and reproduction efficiency. This review summarizes and highlights key nutritional approaches to support the remarkable metabolic adaptations ruminants are facing during the transition period and to reduce heat stress effects and evaluate their beneficial effects on animal physiology, performance, health, as well as welfare.